# -*- coding:utf-8 -*-
class Robot:
    population = 0

    def __init__(self, name):
        self.name = name
        print("(Initializing {})".format(self.name))
        Robot.population += 1

    def die(self):
        print("{} is being destroyed!".format(self.name))
        Robot.population -= 1

        if Robot.population == 0:
            print("{} was the last one.".format(self.name))
        else:
            print("There are still {:d} robots workign.".format(Robot.population))

    def say_hi(self):
        print("Greetings, my masters call me {}.".format(self.name))

    @classmethod
    def how_many(cls):
        print("We have {:d} robots.".format(cls.population))

droid1 = Robot("R2-D2")
droid1.say_hi()
Robot.how_many()

droid2 = Robot("C-3P0")
droid2.say_hi()
Robot.how_many()

print("\nRobots can do some work here.\n")
print("Robots have finished their work. So let's destroy them.")
droid1.die()
droid2.die()

Robot.how_many()